The problem of diffraction by a homogeneous dielectric wedge irradiated by
a time-harmonic plane wave at skew incidence is represented by uncoupled Fr
edholm integral equations of the second kind. It is shown that there exists
a unique solution if the wave numbers of the exterior and interior media a
re suitably restricted; the result covers also the case in which the wave n
umbers are real and the wedge is optically denser. A complete asymptotic ex
pansion is obtained for the solution in the neighbourhood of the edge. The
electric field transverse to the edge becomes singular at the edge, and the
singularity exponent does not depend on the skewness of the incidence. Fin
ally, it is shown that lateral waves appear along the wedge faces also for
plane-wave incidence.